Here in Los Angeles you can't turn on the radio or television, read the newspaper, or even drive on any freeway in the region (including the San Joaquin Valley!) and not know about the upcoming closure of a 10 mile stretch of the San Diego Freeway for the entire weekend of July 16 (including late Friday night and early Monday morning). And it's not any 10 mile stretch of the I-405--it's the stretch between the Santa Monica Freeway and the Ventura Freeway, which practically speaking is the only route that connects the San Fernando Valley and West Los Angeles.
Given the car culture of Los Angeles where people will drive two blocks to go to the gym, this portends a traffic jam of massive, if not biblical proportions. I remember maybe 10 years ago when a traffic accident closed the Hollywood Freeway for several hours on the portion that connected Hollywood to the San Fernando Valley. That created the worst single point traffic jam that Los Angeles has ever seen (the overall congestion for the 1992 riots was worse). Since the accident blocked traffic from going from Hollywood to the Valley, when I left my office in West Los Angeles and headed home to the Hollywood Hills, I didn't think I'd be affected since I was going completely in the opposite direction, and nowhere near the San Fernando Valley. Wrong. Cars looking for a way, any way to go west and north into the Valley clogged the streets in my eastbound direction, as they drove round and round in vain for a clear path home.
Now the San Diego Freeway is not literally the only way to get from West Los Angeles to the Valley. There's Sepulveda Blvd., which largely parallels the freeway. But wait, Sepulveda will be restricted, too. Presumably those working on the freeway construction need that street for their own access, as well as local access for neighborhood residents. Also, there are the canyon roads like Beverly Glen, Coldwater Canyon and Laurel Canyon that connect the Valley to the Westside. Plus there are those secret residential shortcuts that can get you from here to there if you know where to make the correct turns. But no way can they handle more than a small portion of the traffic between the Valley and the Westside.
Optimistically our city fathers point to the 1984 Olympics as demonstrating that advance warning as to potential traffic gridlock will lead to smooth flowing traffic as people avoid the trouble spots in droves. Actually, I think a better precedent is in the Bay Area, when the Bay Bridge between San Francisco and Oakland was closed for Labor Day a couple of years ago, and traffic turned out to be fine. Theoretically that should have been worse since there are fewer ways to cross San Francisco Bay than to get between West L.A. and the San Fernando Valley. Hopefully that will be the best portent of what will actually happen.